324 PROF. EHRENBERG ON ANIMALS OF THE CHALK 
I further enumerated at that time, among the widely-diffused 
caleareous-shelled animals of the chalk, Globigerina bullacea 
and helicina, Rosalina globularis, and Textilaria aciculata, with a 
note of interrogation, all which Polythalamic forms had been an- 
nounced by D’Orbigny as at present living only in the Adriatic _ 
sea, or in the ocean. : 
Although even at that time this greater number of forms en- 
tirely similar to recent ones and not to be distinguished from 
them very much excited my attention, still it appeared to me 
best merely to mention them en passant, for this reason, that the 
same difficulty in pronouncing an opinion existed with regard to 
these forms that attended the Terebratule, viz. that they were 
precisely such species of Infusoria and Polythalamia as were 
least characterized by their form; besides, I had never myself 
observed the living forms of these Polythalamia, and had fre- 
quently, in forms of microscopic animals apparently similar, 
subsequently discovered distinguishing characters. It appeared 
indeed to me very remarkable, but as yet unfit to be a scientific 
basis for further conclusions. 
Besides these forms, M. von Hagenow, in 1839*, specified, as 
a constituent of the white chalk of Riigen, Oculina virginea 
under the name of Lithodendron viryineum, according to Gold-— 
fuss. It is there observed that it is only the young brood of the 
now living form, whence therefore it is at the same time evident 
how little safety there can be in any conclusions with regard to — 
identity, as our views can be attended with any degree of cer- 
tainty only when the various states of age occur together. F 
Il. Incitements to further Inquiry. 
a. Preliminary considerations. ; 
Notwithstanding the numerous recorded observations which — 
have just been mentioned, several of the most eminent English 
geologists, together with some French philosophers of considera-_ 
tion, and the naturalist of Neufchatel the best fossil ichthyolo- — 
gist of our day, have continued to consider the fossil organisms of 
the chalk as being all distinct from still existing similar bodies, as 
is stated in Bronn’s Lethea, p. 771, and in the above-mentioned — 
works. Thus, then, the idea of the Kocene or dawning period — 
of the organisms still existing with us above the chalk has found — 
mate E if 
* Monographie der Rugenschen Kreide Versteinerungen, von Dr. vy. Hagenow 
in Leonhardt’s Jahrbuch fiir Mineralogie, 1839. 
